Simplified Capture, Extraction, and Amplification of Cellular DNA from Water Samples

DNA analysis in water samples is attracting attention in various fields. However, conventional methods for DNA analysis require a work-intensive and time-consuming sample pre-treatment. In this study, a simplified pre-treatment method for analyzing DNA in water samples was evaluated. The process consists of filtration, DNA extraction, and amplification, which can be achieved within a short time. In the filtration process, two types of filters, firstly a tissue paper (Kimwipe) and then a glass filter (GF/F), were used in sequence. The first large pore size filter enabled a reduction in filtration time by removing large particulate matter impurities present in river water matrix. Cells spiked into 1 L of river water were recovered at more than 90% within approximately 5 min filtration time. Also, DNA was extracted from the captured cells directly on the surface of the filter in only 5 min. Thus, DNA collection and extraction from a water sample can be completed within about 10 min. Furthermore, PCR amplification was performed directly from DNA-attached filter sections, which greatly reduced the number of required pre-treatment steps. Finally, we succeeded in establishing a simple and fast on-site pre-treatment system by using a hand-driven syringe filtration method. This pre-treatment system is expected to offer the possibility for the future establishment of a rapid and easy DNA analysis method applicable to various types of water samples.